6.0 valve sound

[flpowerstroke]

on a cold start its like the turbo doesnt engage for like maybe a 2 second delay. when it does engage there is a sound like a valve is opening up. what could this noise be?

[mike 6.0]

What year is your truck? Is this truck new to you? What has changed other than the cold?

[flpowerstroke]

it is a 05 i have had it since new. It just started to do it last week and it only does it if the truck has been sitting for a couple of hours. the sound is like when i start the truck i have the noise of the motor then i hear something open then i hear my turbo.